USDA Zone 11: Where is it? What to Plant? Tips to Success
For a small percentage of Americans, their properties will fall under the USDA hardiness zone 11. This zone encompasses some of the hottest regions in the USA, with long, hot summers, warm shoulder seasons, and very mild winters being the norm in every area.
If you are planning to start a garden of your own in USDA Zone 11, there are a few things you should know first. Understanding the zone your property falls under will make it easier for you to choose what you want to plant, and when you can begin planting, among other things.
What is Zone 11?
Zone 11 is one of the 13 hardiness zones set out by the United States Department of Agriculture as detailed on their Plant Hardiness Zone Map. These 13 zones were used to establish the minimum average winter temperatures in every state and territory in the US, including Alaska, Hawaii, and Puerto Rico.
These zones extend across the United States, running in a latitudinal line from north to south. The further north the zone is, the lower the number will be, and the lower the minimum average temperatures will be, and vice versa.
Each zone also experiences different frost dates, which tell you when you can plant during the winter months.
Zone 11 experiences virtually no frost in winter, and while this means that zone 11 gardeners technically have a year-round growing season, it also means that they have more of a limit on what they can grow compared to zones at lower temperatures. Summer temperatures in this zone are so high that many species of trees, vegetables, flowers, and other plants simply will not survive the heat.
In Key Largo, Florida, summer temperatures can soar to 100 degrees F, which is typical for zone 11 summers, though they rarely exceed that.
This zone is predominantly relegated to coastal southern pockets of the US, as well as Hawaii, Puerto Rico, and the Florida Keys archipelago.
Where is Zone 11?
As the hottest zone in the continental United States, zone 11 only appears in a few states, and only in the hottest areas of the country.
Zone 11 regions are in the southwest, starting on the southern coast of California and slightly east toward Arizona (however it does not appear in Arizona itself). It then reappears at the southern tip of Florida.
Outside of the continent, it is also found inland on every major island in Hawaii, though it is least prevalent on Oahu and most prevalent on the Big Island, Maui, and Kawaii.
It also appears in a small pocket of inland Puerto Rico, north of Yauco around Maricao and Adjuntas.
Minimum Average Temperatures in Zone 11
The basis of all USDA hardiness zones is their minimum average temperatures in winter within 10 degrees F. These temperature ranges are what differentiate them from one another.
Each zone is also split into two subzones, marked as A and B.
- Zone 11: covers minimum average temperatures of 40 to 50 degrees F.
- Zone 11a: this subzone covers minimum average temperatures spanning from 40 to 45 degrees F.
- Zone 11b: this subzone covers minimum average temperatures spanning from 45 to 50 degrees F.
Minimum average temperatures are only a guideline for the coldest winter temperatures you can expect in your region. These temperature ranges can fluctuate from year to year, and from place to place, depending on any unexpected weather patterns that may occur.
Frost Dates in Zone 11
Another aspect of growing zones that gardeners typically need to know is annual frost dates. These dates tell us when the first and last periods of frost are likely to occur in our region. And in turn, they tell us when to begin and finish growing crops that are sensitive to frost.
- Last frost dates: N/A
- First frost dates: N/A
Unlike the growing zones before it, the zone 11 climate is so hot that there are no frost dates for gardeners to take into account. For this reason, zone 11 gardeners can enjoy a year-round growing schedule.
Zone 11 States
Most states in the US fall under multiple growing zones, and these zones can vary widely. For example, parts of California fall under every zone from 5a to 11a.
Zone 11 appears in only 3 US states and 1 US territory. These include:
In the continental US, only subzone 11a appears in California and Florida. 11b is present only in Hawaii and Puerto Rico. Even in these states zone 11 is relegated to tiny pockets in the south and near the coast of California, and also encompassing the southern tip of Florida and the Florida Keys.
By comparison, the next zone down in temperature range, USDA zone 10, is found in seven US states.
When to Plant in Zone 11
While there are many varieties of shrubs, trees, and perennial flowers that will not survive zone 11’s sweltering summer weather, there are plenty of vegetables and herbs that can be grown from seed to harvest.
Cool-weather crops should be planted around late fall and early winter, whenever temperatures begin to drop and the soil can safely accommodate these vegetables. This way, you can ensure a full harvest before the intense summer temperatures hit. Leafy vegetables such as lettuce, spinach, and kale are particularly sensitive to cold so be sure to begin planting them between September and January.
The growing season for warm-weather crops is much longer, and gardeners can pack in multiple plantings from seed to harvest as long as each plant is sufficiently watered and protected from blazing summer temperatures according to their specific needs. The most heat-tolerant crops, such as bell peppers, tomatoes, and okra, will have the best chance of growing all through the summer with the least amount of maintenance.
Tips for Gardening in Zone 11
Knowing your minimum average temperatures for winter is one thing, but there is plenty more to take into consideration when gardening. Here are some useful tips for planting in the zone 11 climate.
- If you wish to grow cool-weather leafy vegetables, such as beets and radishes, consider purchasing starter plants instead of seeds. This will give you an early start in winter, allowing them to reach harvest safely before the hot weather arrives.
- Protection from hot weather is essential in zone 11 as the, at times, overbearing heat is likely going to be your garden’s greatest obstacle. There are many ways you can shield your plants from the hottest parts of the day, whether by using shade sails, planting them near taller plants and trees for natural shade, mulching, or planting in containers that can be moved indoors during the hottest spells.
- Depending on where you live, soil in the hottest zones can be overly dry, poor-draining and overall lacking in the nutrients that your plants need to thrive. Prepare your soil by turning it and adding compost or building raised garden beds to give your plants the best start possible.
- If you live in a particularly dry, arid zone 11 climate that experiences water restrictions in summer, you should favor plants with lower water requirements to ensure your crops receive adequate irrigation.
- When buying seeds, check your seed packets for extra information on planting time, maturation dates, and soil and temperature requirements.
Choosing Plants for Zone 11
Zone 11 is a relatively uncommon growing zone to live in, particularly in the continental US, so getting all of the planting information you need can be difficult. Not to mention, long, hot summers and a complete lack of frost dates or cold weather means that zone 11 gardeners have a unique set of challenges that most US gardeners will not face.
When it comes to choosing plants for zone 11, the first thing you should do is visit your local garden centers and tree nurseries. Here you’ll find a useful range of trees, plants, and seeds that can thrive in your climate. Some employees are even well-equipped to share advice on local gardening.
Seed companies are also useful, as their seed packets and websites often provide supplemental information on growing requirements and planting windows, which will make it easier to choose appropriate species.
Consult friends, family, and acquaintances in your area who may have years worth of gardening experience that makes them an expert on things like local microclimates and atypical weather patterns.
Beginner gardeners should make use of native plants and trees, which tend to be hardy and low-maintenance, and perennials, which only need to be planted once in order to live and produce for years.
What to Grow in Zone 11
With enough information about regional temperature ranges, gardening schedules, and tips for zone 11 gardeners, the next step is to understand what you can grow in this hot climate.
Due to long, hot summers, there is more of a limit on what you can grow in zone 11 compared to lower hardiness zones, but there are still plenty of choices to make. Let’s take a look at some of the most popular trees, vegetables, flowers, and herbs in your region.
Trees for Zone 11
While many of the more conventional US fruit trees will not survive the zone 11 summers, there is a range of delicious and unique tropical, sub-tropical and Mediterranean fruit species that will thrive on your property.
- Mango tree: Growing a mango tree in your backyard may not be the simplest task, but it certainly is a rewarding one. Its large green leaves and white flowers add plenty of appeal to your garden, as well as a pleasant tropical fragrance and delicious mango fruits in summer. Mango trees grow best in frost-free climates with long, hot summers, making zone 11 the perfect zone for these fruit trees! For best results, plant your tree directly into the ground (avoid container planting) in early spring, in an area with full sun and well-draining soil.
- Olive tree: Sunny olive trees don’t just thrive in the Mediterranean – they can also grow well in certain parts of the USA. Olive trees love heat and sunshine and grow best in zones 9-11. Due to their delicate silver-green foliage and fragrant white flowers, they make an excellent focal point for your garden and in border planting. Be sure to choose a European olive trees variety, such as the Frantoio or Leccino. Research wisely, as some will thrive in zone 9-10 but will not crossover to zone 11 temperatures.
- Lime trees: If you want to grow your own limes in your zone 11 backyard, you’re in luck! Lime trees grow best outdoors in zones 8 through 11. They are not large trees, growing up to 20 feet at most, and bear small and fragrant white and yellow flowers. Consistent watering, well-draining soil, and plenty of fertilizer are key to a healthy lime tree. Lime tree varieties that do well in zone 11 include the Kaffir, Mexican Key, Persian, and Australian Finger lime.
- Other fruit trees: Common guava, papaya, soursop, persimmons including Fuyu, Izu, Suruga, dragon fruit, avocados such as the Gwen, Hass, and Mexicola Grande, bananas such as the Dwarf Cavendish, Grand Naine, Lady Finger, Blue Java, and Musa Velutina, Navel and Calamondin orange, Ruby Red grapefruit, Owari Satsuma, lychees including the Hakip, Brewster, Kaimana, and Mauritius, longans including Kohala, Wu Yuan, BiewKiew, Sri Champoo, and Haew, prickly pear cactus, acai palm, jackfruit tree, breadfruit tree
In any landscape, flowering trees become a focal point, bringing life and fragrance into your spring and summer garden. Here are some of the most beautiful flowering trees that can be established on your zone 11 property.
- Yellow Trumpet Tree: This South American flowering native will brighten any landscape with its vivid show of yellow trumpet-shaped flowers that burst into bloom in early spring. The yellow trumpet tree is highly tolerant to heat and drought and can grow easily in the majority of soil types, making it an excellent option for gardeners in hot, arid climates. This glorious tree does well as a specimen tree, street tree, and patio tree, and attracts plenty of pollinators to your backyard. It grows exclusively in USDA hardiness zones 9, 10, and 11.
- New Zealand Christmas Tree: The New Zealand Christmas Tree, more commonly known in New Zealand as the Pohutukawa, is a festive icon in its pacific home. In the US it will only grow in zones 10 to 11, producing incredibly vibrant red bottlebrush flowers in the middle of summer. These trees are hardy and highly tolerant to drought, salt spray, urban pollution, and smog, and are best used as a specimen or shade tree.
- Tipu: Another South American native that will thrive in the heat of zone 11, the exotic Tipu tree, or Tipuana tipu, is a flowering legume tree sometimes used as an accent, shade or landscape tree. These trees bear delicate orange-yellow flowers that eventually turn into the brown seed pods of the tipu fruit. While these trees are beautiful, one must think carefully before planting – their aggressive root system can disrupt concrete and asphalt, and their flowers and pods can make a mess through summer and fall.
- Other flowering trees: Orchid tree, Acacia, Jacaranda, Silk oak, Royal Poinciana, Golden Shower, Geiger tree, Lignum Vitae, Royal Empress, Himalayan Champaca, Firecracker plant, Koa, Breadfruit, Sausage tree, Coast Sandalwood, Cannonball tree, Tamarind, Hawaiian Sandalwood
The most common type of evergreen trees hardy to zone 11 are palm trees, though there are a number of other species that can grow well here. These trees will provide your property with color and texture throughout every season of the year.
- Bismarck Palm: A unique and very desirable landscaping tree, the Bismarck palm makes an elegant and eye-catching focal point for any zone 11 garden. These ornamental palms are most notable for their pale gray and green palmate leaves and a stout trunk. Their foliage can soar as wide as 4 feet across, and for this reason, it is not recommended to plant a Bismarck in a small garden or backyard as they have a tendency to take over. Otherwise, they are a stunning and low-maintenance addition to your landscape.
- Aleppo Pine: The Mediterranean Aleppo pine is an evergreen conifer that does well in a hot, dry environment. Most often found in southern Europe and the middle east, these hardy heat-loving trees will only thrive in USDA zones 9 to 11. Unlike many other pine species, they have a naturally rounded growth habit, but they can be pruned to control their shape and height. This evergreen is relatively low-maintenance, drought-resistant, tolerant of wind and salt spray, and grows in a wide variety of soil types.
- Needle Palm: A rather shrubby palm tree, the needle palm typically grows to less than 10 feet tall, making it a rather compact evergreen addition to your landscape, perfect for small zone 11 gardens. Its thin, glossy green leaves grow clustered together, providing a burst of color year-round. The needle palm is easy to grow and maintain, is disease and pest resistant, and is perfect for filling any empty space in your garden.
- Other evergreen trees: Bismarck palm, California Fan palm, Chinese Fan palm, Needle palm, Acai palm, Date palm, Canary Island Date palm, Mexican Blue palm, Spindle palm, Sago Palm, Eucalyptus, Screwpine, Cook pine, Slash pine, Silk oak, Jhalna, Hawaiian sandalwood, Parana Pine, Pigeon Plum
Zone 11 offers some of the most unique and eye-catching native trees in the US. These trees are hardy and heat-loving, as well as fairly easy to care for.
- Gumbo Limbo: A south Floridian native, the amusingly-named gumbo limbo is a unique, hardy tropical tree that thrives in the heat of zone 11 – in fact, it is only hardy to zones 10b and 11a and b. The gumbo limbo is a fast-growing native and its canopy can exceed 60 feet in diameter, according to the National Park Service website. It is most notable for its unusual growth, its rounded branches growing in a curved pattern that both soars up to the sky and down low to the ground.
- Lignum Vitae: This beautiful broadleaf evergreen is native to Florida, Central America, and South America. Its name translates to “Tree of Life,” and is known for its extremely dense, heavy wood. It is a lovely accent plant or specimen plant, due to its evergreen leaves, wide branching trunks, and exceptionally beautiful blue-purple flowers, and it also grows well in containers and around patios. Like the gumbo limbo, this tree is also restricted to growing zones 10B to 11. It is tolerant to drought, salt, and most notably, hurricanes.
- Blue Paolo Verde: The state tree of Arizona, the blue paolo verde is a popular native tree known for its blue-green foliage and fragrant yellow spring flowers. It is a tree most associated with desert climates, with a hardy, adaptable nature and low water requirements, making it perfect for gardeners living in hot, dry climates. It’s the perfect zone 11 native to add a pop of color and texture to your environment all year round.
- Other trees: Arizona Ash, Koa, Screwpine, Hawaiian Tree Fern, Candlenut, Geiger tree, Gumbo-Limbo, Coast Sandalwood, Pigeon Plum, Coral tree, Buttonwood, ʻōhiʻa lehua, Trumpet tree, Hawaiian False Mulberry, Ceiba tree
Vegetables for Zone 11
For gardeners who want to add a nutritious (and delicious) element to their garden, these vegetables do well in the long summers and mild winters of zone 11.
- Bell Peppers: A sweet pepper that lacks the heat of its spicier counterparts, the bell pepper is a crunchy and satisfying warm-weather vegetable that is harvested as green, red, and yellow peppers. Bell pepper plants will also grow relatively easily, so long as their needs are met. These plants must be protected from any cold weather, and need consistent temperatures of at least 50-60 degrees F before they will begin producing. It will take 2 months or more before your bell peppers reach harvest.
- Okra: This warm-season crop thrives in long, hot summers, which is why it is such an ideal planting option for zone 11 gardeners. Though these flowering plants are sometimes grown as ornamentals, they are most often planted for their distinctive edible green seed pods. Okra seeds can be sowed once soil temperatures reach 65 to 70 degrees, and will typically reach harvest within two months. These plants tolerate a dry climate, but still need consistent watering to produce maximum yields.
- Taro: A staple of the native Hawaiian diet, it’s no surprise that this tropical tuber grows well in the zone 11 climate. The entire plant can be eaten, with the tubers being particularly nutrient-dense, and its large glossy leaves add ornamental value to any garden. This herbaceous perennial requires long periods of consistently hot weather, with temperatures between 77 to 95 degrees F, and takes up to 200 warm days before it will reach maturity. It prefers humidity and rich, well-draining soil.
- Other vegetables: Kale, beets, cabbages, radishes, sweet potatoes, tomatoes, bitter gourd, eggplants, beans, cape gooseberries, arugula, celery, carrots, cauliflower, lettuce, summer squash, corn, cucumbers, potato, pumpkin, zucchini, tomatillos
Perennial Flowers for Zone 11
Though heat-loving perennial flowers are not the easiest to find in zone 11, these plants will brighten your garden year to year.
- Hibiscus: With varieties both native to the southern US and imported from Asia, heat-loving hibiscus flowers come in many different types, and are typically hardy from zone 4 all the way up to zone 11. There are around 200 species of hibiscus that come in pinks, reds, oranges, yellows, and more. These beautiful trumpet-shaped blooms add a touch of the tropical to any landscape, as well as attract plenty of local pollinators. These plants typically produce flowers from late spring to fall.
- Bahama Cassia: A favorite of many Floridian flower gardeners, the Bahama cassia is a small, upright, perennial flowering shrub. It blossoms with pretty, buttery yellow flowers that can bloom throughout the year, which is part of its enormous appeal for zone 11 gardeners. It can reach up to 9 feet tall and works well as a specimen, border plant, or even as a hedge or screen. It is also known for attracting plenty of butterflies. Keep in mind that the Bahama cassia is relatively short-lived, lasting only four or five years.
- Amaryllis: With its ornate and boldly-colored trumpet-shaped flowers, the amaryllis is a highly sought-after perennial flower that can be grown both indoors and outdoors. These flowers tend to come in reds, whites, pinks, and apricot. In zone 11, amaryllis is best grown outdoors, in fertile, well-draining soil, and will typically bloom for 7 weeks or more. According to the University of Minnesota Garden Extension, the Amaryllis flowers commonly bought and sold in the US are hybrids of the genus Hippeastrum.
- Other perennial flowers: Leavenworth tickseed, Elliott’s aster, bougainvillea, dahlia, datura, salvia, four o’clock, Arizona poppy, brittlebush, devil’s claw, fairy duster’s
Herbs for Zone 11
Adding both culinary purpose and beauty to your garden, these useful and heat-tolerant herbs are an excellent addition to any property.
- Lemongrass: With plenty of ornamental appeal and culinary properties, lemongrass is an absolute double-whammy for zone 11 gardeners. Lemongrass is a fast-growing native to India and Sri Lanka, so it naturally grows best in warm, humid environments. This fragrant herb loves full sun, rich soil, and consistent watering, requiring little else to grow and thrive. It is a perennial that can benefit from being cut back each year to control growth, keep it neat and remove any dead leaves.
- Lemon Verbena: This south American native is prized for its lemony fragrance, small white flowers, and glossy leaves which are used as an ingredient in perfume making, medicine, and desserts and beverages. Aside from its practical usage, it is also a very attractive plant and can be grown as a border plant or focal shrub for your garden. Lemon verbena is relatively easy to grow both in the ground and in containers, just make sure to start from a cutting rather than seeds.
- Spearmint: Many species, hybrids, and cultivars are included in the mint family, but not all of them are tolerant to heat. However, one of the most adaptable and popular species of mint is spearmint, which can grow and thrive in zone 11. This aromatic perennial has significant medicinal and culinary uses and is very easy to grow in the right conditions. Just keep in mind that spearmint can spread easily and even take over parts of your garden, so some pre-planning and maintenance are needed to keep this herb in check.
- Other herbs: basil, chive, Mexican oregano, dill, parsley, marjoram, French tarragon, coriander, thyme, mint, rosemary, fennel
The Zone is Only Part of the Story
Understanding which USDA hardiness zone you live in, and how that affects the climate and weather patterns in your area, is a vital part of establishing your home garden. With this information you have a better understanding of what trees, plants, and vegetables you can grow, and when you can begin planting them.
But getting familiar with the minimum average temperatures around your property is only the beginning – there is much more you need to know. Learning about local microclimates and soil types, as well as the specific growing requirements of everything you wish to plant, is also important.
Understanding your environment, and your plants needs, will allow your zone 11 garden to survive and thrive even in some of the hottest regions of the USA.